During oil and gas underwater field development, slender structures such as umbilicals and flexible are commonly used. Such slender structures can be vulnerable to underwater current induced vibration. In order to evaluate the effects of such vibrations on the slender structures, the damping characteristics of such slender structures are needed. However, the damping characteristics of the umbilicals and flexible are not well understood.
Many umbilicals and flexibles are constructed using small tube bundles or different functional layers. When these slender structures are subject to external force excitations, such as underwater current, their motions are dependent on the structure damping effect, which is related to the slender structure vibration amplitudes and frequencies. Oftentimes in the oil and gas industry, it is assumed that the damping is linear, and typically around one percent (1%) for umbilical and five percent (5%) for flexible. However, such linearized approximation is oversimplified and cannot be used to sufficiently identify the damping characteristics of the slender structures because of the complex nature of such slender structures, the damping behavior of which may not be linear. Apparatus and methods can be designed to test the damping behavior of certain umbilical and flexible samples, and the damping characteristics of such samples can be obtained to aid optimizations and applications thereof.